Blanketing medium for chemical fusions and method of making same



H. H. DOW. BLANKETING MEDIUM FOR CHEMICAL FUSIONS AND METHOD OF MAKINGSAME.

APPLICATION FILED FEB. 19, 1919. 1,41 1A21, Patented Apr. 4, 1922.

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HERBERT H. DOW, OF MIDLAND, MICHIGAN, ASSIGNOR T0 THE- DOW CHEMICALCOMP, OF MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN,

BLANKETING- MEDIUM EOR CHEMICAL FUSIQNS AND METHOD OF MAKING SAME.

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Specification of Letters Patent.

Patented Apr. 4, 1922.

@rflginal application filed August 31, 1918, Serial No. 252,225. Dividedand this application filed February 19, 1919. Serial No. 278,090.

' Toall whom it may concern:

Be it known that I, HERBERT H. Dow, a citizen of the United States, anda resident of Midland, county of Midland, and State of Michigan, haveinvented a new and useful Improvement in Blanketing Media for ChemicalFusions and Methods of Making Same, of which the following is aspecification, the principle of the invention being herein explained andthe best mode in which I have contemplated applying that principle, soas to distinguish it from other inventions.

There are many fusion processes in which the mixture of materials, u onbeing heated together in order to cause t eir interfusion, develop atendency to oxidize excessively when exposed to the oxygen in theatmosphere.- This is particularly true of fusion processes having to dowith the preparation of organic compounds, such as fusions in causticsoda, or other alkali metal hydrate. It has accordingly been foundadvisable to blanket the fusion mixture with a suitable gas or vapor inorder to protect such mass from oxidation, and I have found that forthis purpose a sufficiently heavy hydro-' carbon vapor, for instancegasoline vapor, is very satisfactory. However, the fusion kettlesrequire of course to be vented, and, as might be expected, it has beenfound that the hydrocarbon vapor, upon being mixed with air, is very aptto form an explosive mixture. The present invention, accordingly, has asits object the provision .of a suitable blanketing medium for chemicalfusions, together with a method of mak-,

ing the same, it being noted that the present case is a division ofapplicants co-pending application filed August 31, 1918, Serial No.,252,225, for improvements infusion with only a small admixture ofoxygen.

' processes (since issued into Patent No.

vention, such disclosed mode, however, constituting but one of the,various ways in which the principle of the invention may be used.

In said annexed drawing, the single figure there appearing illustratesin diagrammatic fashion an arrangement of apparatus for carrying-out mypresent improved process.

Nitrogen alone, if pure, i. e. unmixed with oxygen, would of course bebest suited to blanket the fusion mixture, but is not cheap enough asordinarily made; to be available for commercial use. I have found,however, that while ordinary stack gases contain a small percentage ofoxygen sufficient to cause some oxidation," if admitted directly overthe fused mass, such oxygen content is so small that the formation of anexplosive mixture between the same and a hydrocarbon vapor, such ashereinbefore referred to, is practically impossible.

In the drawing, a fusion pot l oftypical form is shown seated in asuitable furnace chamber 2, whereby1 heat may be applied ordinarily bedesirably brought in contact with a suitable reagent capable ofabsorbing carbon dioxide, such for example as magnesium hydrate, so asto eliminate from such stack gases the carbon dioxide present. In thisWay a valuable by-product in the form of magnesium carbonate isproduced, and the residue is practically pure nitrogen,

If desired, this residual gas may be utilized to directly blanket thefusion mixture in the pot, but in most cases a neutral hydrocarbonvapor, such. as gasoline vapor,

is preferably introduced into the pot to immediately cover the fusionmixture. Such introduction is conveniently effected by formed, and theduct 5 accordingly serves this purpose, any excess of vapor beingexpelled into the larger flue 6 through which the stack gases pass; or,in the event of a reflux of the vapor into the pot, the stack gases willnot form an explosive mixture with the hydrocarbon. However, the amountof .oxygen in the mixture will be re- :luced to quite an inconsequentialpercentage, so no harm results from contact bezween the same and themixture.

Other modes of applying the principle of my invention may be employedinstead of ;he one explained, change being made as re- ;aIds thecomposition and method herein :lisclosed provided the ingredients orsteps stated by any of the following claims or the :quivalent of suchstated ingredients or ;teps be employed.

I therefore particularly point out and iistinctly claim as-myinvention 1. The method of making a neutral blanketing medium forachemical fusion which consists in preliminarily treating flue gases toremove the carbon dioxide and then adding the resultant gases to ahydrocarbon vapor to form the blanketing medium.

2. The method of making a neutral blanketing medium for achemical fusionwhich consists in preliminarily treating flue gases by passing same overmagnesium hydrate whereby the carbon dioxide therein is absorbed withthe formation of magnesium carbonate resulting in a practically purenitrogen residuum, and then adding such residuum to a hydrocarbon vaporto form the blanketing medium.

3. A blanketing medium for chemical fusions and the like consisting offlue gases from which the carbon dioxide has been removed, andhydrocarbon vapor.

Signed by me, this th day of February,

HERBERT H. DOW.

